Both stressed that while they made the call to King Edward VII Hospital, they did not have a say on whether it went to air. The call was recorded and then went through a vetting process at their network, Southern Cross Austereo, before it was broadcast, they said.

"This was put through every filter that everything is put through before it makes it to air," Christian said in an interview with the program "A Current Affair."

But Christian said he did not know what that vetting process entailed.

"I'm certainly not aware of what filters it needs to pass through," he said.

"Our role is just to record and get the audio," Christian told "A Current Affair."

Greig and Christian said they never expected the prank call to be successful.